The present invention relates to a method and apparatus for integrally forming a cutter on a carton blank to be folded into a carton. More specifically, the present invention relates to such a method in which a paperboard is shaped into a profile substantially the same as the carton blank, the paperboard is integrally formed with saw-teeth on an edge portion thereof and the teeth are hardened by an application of a quick drying adhesive including .alpha.-cyanoacrylate, thereby producing a carton blank for folding into a carton having an integral cutter; and an apparatus for performing the above method.
A variety of containers for accommodating a wrapping web, such as wrapping film, aluminum foil or thin paper sheet for wrapping foods, drugs and the like, are well known. Exemplary of such containers are wrapping web containers constituted as cartons made of, for instance, paperboard having a thickness of approximately 0.3-0.5 mm, and capable of accommodating a roll of wrapping web so as to be freely rotatable therein. Such cartons are provided with metallic cutters for transversely severing web portions unrolled and extracted from the web roll by the user.
In Japanese Utility Model Application No. 63-10064, the present inventor has proposed a cutter defined by saw-teeth hardened by application of a quick drying adhesive including .alpha.-cyanoacrylate. One cutter of this type is formed directly on an edge portion of a front wall of a carton blank for forming the carton. The cutter is used instead of the conventional metallic cutter for cutting a wrapping web on the upper edge of the carton box. In the process of forming the cutter, a carton board having a profile generally corresponding to the final carton is fabricated from fiberboard or paperboard, and a series of cutting teeth, like saw teeth, is integrally formed on an edge of the carton board by a blanking or die-cutting process. A quick drying adhesive including .alpha.-cyanoacrylate is then applied to the toothed edge, so that the toothed edge is hardened by the adhesive to a degree enabling it to cut the wrapping web.
While the above-described process fulfills its purpose, it has been found that where the toothed edge is made in a single step in which the carton board is cut by a conventional blanking tool or die cutter having a saw teeth profile, the apex of each tooth is compressed and partially deformed by the die-cutting pressure. This deformation may cause the apex to be rounded and thinned to such an extent that the toothed edge will not maintain the required strength.
Moreover, small pieces of paper and dust generated in the blanking or die-cutting process remain on the toothed edge and are entrained thereby. Such pieces and dust may contaminate a bath of the adhesive in which the toothed edge is immersed following the blanking process. Otherwise, the pieces and dust remain adhered to the toothed edge and degrade the appearance and quality of the finished cutter.
Further, while the fabrication of the cutter in the aforesaid manner enables the carton to be produced in a relatively short time because the adhesive dries naturally and cures quickly to impart the toothed edge with adequate strength, a further shortening of the drying time is desirable in view of the requirements ragarding mass-production of the carton blanks.
In addition, since no apparatus for carrying out the above method automatically and successively has been developed, it has not been possible to economically mass-produce carton blanks with integral cutters.